Critical Thinking-this site breaks up its information into theory, practice, and evaluation.
Critical and Creative Thinking - Bloom's Taxonomy-this site has overview materials plus links to a variety of sites.
Critical Thinking-a quick overview site.
    Learning and Studying Guides Index-this is an University site but has ideas for learning.
Strategies for Teaching Critical Thinking-an overview article on Critical Thinking.
Center for Critical Thinking Resource Center-a variety of Interent links.
    Structures for Student Self-Assessment
    Center for Critical Thinking Classroom Materials-includes instructional guides and lessons.
Critical Reading: A Guide-an article that talks about how to critical read different types of materials.
Critical Thinking & Problem Solving Skills-this site has general information and lesson plans.

Questions and Questioning: The Most Powerful Technologies of All-an article talking about the importance of developing the ability to question.
Essential Questions-this article talks about the criteria for essential questions and provides some examples.
Classroom Strategies to Engender Student Questioning-this site provides some suggestions on how to have students develop their own meaningful questions.

Problem Based Learning

Problem Based Learning
http://www.iss.stthomas.edu/studyguides/pbl.htm
ASCD PBL Tutorial -- Scroll down and click on Problem Based Learning.
http://www.ascd.org/frametutorials.html
Creating and Implementing Student-Centered Web Based Activities
http://www.amphi.com/~pgreenle/pbl/index.html